Waffle iron



N W A 9 i G m v.

/7/GINVENTOR V/r/ar 6 Way/raw WETNESSES' ATTORNEY so contour, but are 7 35 mold 16 is provided Patented Aug. 14, 1928.

UNITED STATES PATENT OFFICE.

VICTOR G. VAUGHAN, F MANSFIELD, OHIO, ASSIGNOR, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OE PENNSYLVANIA.

WAFFLE ,moiv.

Application filed ma 11,

My invention'relates to electrically heated appliances and particularly toel ectrically heatedwaflle irons. v

An object of my invention is to provide a relatively simple, inexpensive, highly efiicient and easily replaceable heating unit for awafile iron.

In practicing my invention, I associate with a. waffle iron embodying the usual casm ings and wafile molds, a heating unit embodying a resilient sheet metal plate of dished form and so shaped. as to provide an annular groove near the periphery ofthe plate. A resistor is held in the groove by expansively-oxidized electric-insulating material and a single element is provided to clamp the heating unit plate against the waflie mold and to hold these elements in proper operative positions within acasing.

In the single sheet of drawings,

Figure 1 is a top plan View of a wafiie iron with which is associated a heating unit embodying my invention, and

Fig. 2 is a view in vertical as through. v

An electrically heated waifle iron 11 comrises a suitable upper casing 12, a lower casing 13 and'a hollow base 14:." The two casings may be of any suitable design and here shown as circular in do not desire to be limited section thereshape although I thereto. 1

A waifle imold 15 is provided for the upper casing and a substantially similar waffle for the lower casing, which molds are of a size and contour to fit into the respective casings in the manner shown more particularly in Fig. 2 of the drawings. The 'operative surface of the re- 4 spective molds are ofany suitable kind usually employed in the art, while the inner or rear surfaces thereof are preferably made smooth.

V The hollow base 14 is provided with a number of supporting members 17, which ma be made of a heat-insulating material and which extend below the bottom rim of the base in order to raise the'same above the surface of a table upon which the waffle iron is being used.

A heatin unit is 'operatively associated ,with each 0 the waflle molds and embodies in general a dished sheet metal member 18, the central portion of which is provided 5 with. a plurality of radially extending ing a heating unit c ment therewith, such 1927. Serial No. 190,430.

grooves 19 in order th but resilient construction shall be obtained. The member 18 is provided at its periphery with a relatively deep groove 21 for receivo-mprising a resistor wire 22 wound in substantially helical shape and heldwithin the grooved portion by expansively oxidized electric-insulating mate rial 23. This filling of electric insulating material is produced by the method disclosed and claimed inreissue Patent No. 16,340 130 0. B. Backer.

Briefly, the method, disclosed and claimed, in the above numbered patent, comprises sur rounding'thehelically wound resistor with a helically wound strip of initially metallic magnesium, after which the resistorand its envelope of magnesium are placed within the groove2l and the assembled structure is then subjected to the action of either high pressure steam or of hot water, heated in an enclosed casing. The action of this process is to change the initially metallic magnesium to a crystalline Structure of magnesium hydroxide. The volume of hydroxide is substantially 200% that of the initially metallic magnesium. This act-ion provides a means for tightly holding the resistor wire within the groove and also provides a highly efiicient path for conducting the heat generated in the resistor wire toeither the walls of the groove or to an object in engageas the waflle mold shown in the drawings.

Each Wafile mold is provided with a central projection or lug 24,. integral with the mold andloeated at the rear surface thereof, into which a screw threaded stud 25 extends. nut -26 is mounted on the outer portion of this stud and is screwed against the outer surface of the central portionof the disk 18 in order to clamp it tightly against the rear surface of thewafiie mold.

at a sufficiently stitl' The stud 25 is made of .such a length as to receive an ornamental nut havingan enlarged portion located on the outside of the 035111 in order that by screwing down the nut 2i on the stud 25, the w'aflle mold may be tightly clamped against the rim portion of the cooperating casing.

Terminal strips 28 and 29 are provided for. the two heating units hereinbefore described, two such terminal strips being provided for each heating unit, the inner end portions of the respective terminal strips connecting conductors being supported by and insulated from the rear surface of the dished member 18 and connected to the respective ends of the resistor wire 22. These terminal. members are suitably insulated from the member 18 and as they form no part of my invention, they are not further described in detail.

The upper and lower casing members are provided with cooperating.hinged portions 29 and Sl which may be of any suitable or desired type. but. are preferably so made as to embody a hollow hinge pin through which extends a flexible armored conduit or a coiled spring 32, within which are located 33, which are suitably connected to the respective terminal strips 28 and 29. Terminal pins 84 and are insulatedly mounted on 14: and are connected by conductors 36 to the terminal strips 28 and 29 in order to permit of energizing the resistor wires 22 when the terminal pins Stand are connected to a suitable source of supply in a manner well known in the art.

A knob or actuating handle 37, is provided on the upper casing 12 in order to permit of raising and lowering the same during the operation of the device.

It is obvious that there will be a relatively large amount of heat radiated from the peripheral edge portions of the casings an more particularly of the waffle molds, and the diameter of the substantially circular groove 21 bears a definite ratio to the diameter of the waffle molds. This ratio is such that a substantially uniform heat dis tribution is obtained over the entire baking surface of the waffle molds. so that any waffle baked therebetween will be baked substantially uniformly over its entire surface.

The device embodying my invention thus provides a heating unit which can be manufactured entirely separate from and independently of, the other parts the. hollow base I cular contour,

of the wafileiron and which can be operatively associated therewith very quickly and easily, and whose structure is such that it will permit of slight relative expansion movement because of the heating and cooling of the various parts/of the waffle iron during operation thereof. heating unit of this kind can be replace easily and quickly.

Various modifications may be made in the device embed ing my invention without departing from the spirit and scope thereof and I desire that only such limitations shall be placed thereon as are prior art or are set forth in the appen claims.

I claim as my invention:

1. In an electrically heated appliance, the combination with a baking surface, 0 a dished, resilient sheet metal plate having its peripheral portion shaped to provide a groove. a resistor element in said groove, ex aansivelypxidized electric-insulating material in said groove for tightly holding the resistor therein, and means for clamping the grooved surface-of the plate against one side of the baking surface.

2. In a wafile iron, the combination with a plane baking surface of substantially cirand a casing therefor, of a -resilient sheet metal plate shaped to provide an annular groove in one face thereof, a resistor member in said groove, expansivelyded oxidized electric-insulating material sur-- [round ng said resistor to tightly hold It therein, the annular groove being of such diameter to permit the energized resistor to heat the baking surface to a uniform temperature, and a single means for clamping the sheet metal plate against the baking surface and for holding them in the casing.

In testimony whereof, I have hereunto subscribed my name VICTOR Gr. VAUGHAN.

imposed by the this 29 day of April. 

